// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

// Package consensus implements different Ethereum consensus engines.
package consensus

import (
	"github.com/PlatONnetwork/PlatON-Go/common"
	"github.com/PlatONnetwork/PlatON-Go/core/cbfttypes"
	"github.com/PlatONnetwork/PlatON-Go/core/state"
	"github.com/PlatONnetwork/PlatON-Go/core/types"
	"github.com/PlatONnetwork/PlatON-Go/core/vm"
	"github.com/PlatONnetwork/PlatON-Go/p2p/discover"
	"github.com/PlatONnetwork/PlatON-Go/params"
	"github.com/PlatONnetwork/PlatON-Go/rpc"
	"crypto/ecdsa"
	"math/big"
)

// ChainReader defines a small collection of methods needed to access the local
// blockchain during header and/or uncle verification.
type ChainReader interface {
	// Config retrieves the blockchain's chain configuration.
	Config() *params.ChainConfig

	// CurrentHeader retrieves the current header from the local chain.
	CurrentHeader() *types.Header

	// GetHeader retrieves a block header from the database by hash and number.
	GetHeader(hash common.Hash, number uint64) *types.Header

	// GetHeaderByNumber retrieves a block header from the database by number.
	GetHeaderByNumber(number uint64) *types.Header

	// GetHeaderByHash retrieves a block header from the database by its hash.
	GetHeaderByHash(hash common.Hash) *types.Header

	// GetBlock retrieves a block from the database by hash and number.
	GetBlock(hash common.Hash, number uint64) *types.Block
}

// Engine is an algorithm agnostic consensus engine.
type Engine interface {
	// Author retrieves the Ethereum address of the account that minted the given
	// block, which may be different from the header's coinbase if a consensus
	// engine is based on signatures.
	Author(header *types.Header) (common.Address, error)

	// VerifyHeader checks whether a header conforms to the consensus rules of a
	// given engine. Verifying the seal may be done optionally here, or explicitly
	// via the VerifySeal method.
	VerifyHeader(chain ChainReader, header *types.Header, seal bool) error

	// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
	// concurrently. The method returns a quit channel to abort the operations and
	// a results channel to retrieve the async verifications (the order is that of
	// the input slice).
	VerifyHeaders(chain ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error)

	// VerifyUncles verifies that the given block's uncles conform to the consensus
	// rules of a given engine.
	VerifyUncles(chain ChainReader, block *types.Block) error

	// VerifySeal checks whether the crypto seal on a header is valid according to
	// the consensus rules of the given engine.
	VerifySeal(chain ChainReader, header *types.Header) error

	// Prepare initializes the consensus fields of a block header according to the
	// rules of a particular engine. The changes are executed inline.
	Prepare(chain ChainReader, header *types.Header) error

	// Finalize runs any post-transaction state modifications (e.g. block rewards)
	// and assembles the final block.
	// Note: The block header and state database might be updated to reflect any
	// consensus rules that happen at finalization (e.g. block rewards).
	Finalize(chain ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction,
		uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error)

	// Seal generates a new sealing request for the given input block and pushes
	// the result into the given channel.
	//
	// Note, the method returns immediately and will send the result async. More
	// than one result may also be returned depending on the consensus algorithm.
	Seal(chain ChainReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error

	// SealHash returns the hash of a block prior to it being sealed.
	SealHash(header *types.Header) common.Hash

	// APIs returns the RPC APIs this consensus engine provides.
	APIs(chain ChainReader) []rpc.API

	// Close terminates any background threads maintained by the consensus engine.
	Close() error
}

// PoW is a consensus engine based on proof-of-work.
type PoW interface {
	Engine

	// Hashrate returns the current mining hashrate of a PoW consensus engine.
	Hashrate() float64
}

type Bft interface {
	Engine

	// the former round of consensus node ids
	//FormerNodeID() []discover.NodeID

	// the former round of consensus nodes
	//FormerNodes(parentNumber *big.Int, parentHash common.Hash, blockNumber *big.Int) []*discover.Node

	// the current round of consensus node ids
	//CurrentNodeID() []discover.NodeID

	// the current round of consensus nodes
	CurrentNodes(parentNumber *big.Int, parentHash common.Hash, blockNumber *big.Int) []*discover.Node

	IsCurrentNode(parentNumber *big.Int, parentHash common.Hash, blockNumber *big.Int) bool

	ConsensusNodes(parentNumber *big.Int, parentHash common.Hash, blockNumber *big.Int) []discover.NodeID

	// whether the current node should packing
	ShouldSeal(parentNumber *big.Int, parentHash common.Hash, commitNumber *big.Int) bool

	// received a new block signature
	// verify if the signature is signed by nodeID
	OnBlockSignature(chain ChainReader, nodeID discover.NodeID, sig *cbfttypes.BlockSignature) error

	// Process the BFT signatures
	OnNewBlock(chain ChainReader, block *types.Block) error

	// Process the BFT signatures
	OnPong(nodeID discover.NodeID, netLatency int64) error

	// Send a signal if a block synced from other peer.
	OnBlockSynced()
	//CheckConsensusNode(nodeID discover.NodeID) (bool, error)

	//IsConsensusNode() (bool, error)

	// At present, the highest reasonable block, when the node is out of the block, it needs to generate the block based on the highest reasonable block.
	HighestLogicalBlock() *types.Block

	HighestConfirmedBlock() *types.Block

	GetBlock(hash common.Hash, number uint64) *types.Block
	SetPrivateKey(privateKey *ecdsa.PrivateKey)

	Election(state *state.StateDB, parentHash common.Hash, blockNumber *big.Int) ([]*discover.Node, error)

	Switch(state *state.StateDB, blockNumber *big.Int) bool

	GetWitness(state *state.StateDB, flag int, blockNumber *big.Int) ([]*discover.Node, error)

	GetOwnNodeID() discover.NodeID

	SetNodeCache(state *state.StateDB, parentNumber, currentNumber *big.Int, parentHash, currentHash common.Hash) error

	Notify(state vm.StateDB, blockNumber *big.Int) error

	StoreHash(state *state.StateDB, blockNumber *big.Int, blockHash common.Hash)

	Submit2Cache(state *state.StateDB, currBlocknumber *big.Int, blockInterval *big.Int, currBlockhash common.Hash)

	RemovePeer(nodeID discover.NodeID)
}
